Magnetic resonance (MR) imaging may be broadly categorized by whether or not a contrast agent is used. Non-contrast MR imaging (MRI) utilizes one or more intrinsic properties of a subject to generate contrast for producing an image of the subject. More specifically, differences in one or more properties of tissues can be exploited to provide contrast between a target tissue and surrounding tissue. Alternatively, in contrast enhanced MRI, a contrast agent is administered to a test subject. The contrast agent permeates a target tissue (e.g., blood or a designated organ) and generates the necessary contrast between the target and surrounding tissues to produce the resulting image of the subject.
The pulmonary veins (PV) are frequently the subject of MR imaging. In particular, various medical procedures involve working with PVs. Imaging of PVs is often performed before such medical procedures, to facilitate planning of the procedure. Imaging is also often performed post-procedure to assess the results of the procedure. Conventionally MR angiography, and more particularly PV imaging, is performed using a contrast agent. A common contrast agent used for MR angiography of PVs is gadolinium (Gd), which causes a shift in the resonant frequency of a subject to which it is administered. The shift in resonant frequency is utilized to produce the contrast enhanced image.